Sandra Bullock  is one of Hollywood's hottest A-list actresses and she's been lighting up the screen for over two decades . Along the way, Sandra's made many friends and worked with some major names, including Ryan Gosling , Keanu Reeves , Ryan Reynolds , and George Clooney  — but in addition to her killer acting chops , Sandra is probably best known for her lightning-quick wit, sense of humor, and infectious smile. The beloved star turns 51 on Sunday, so we're celebrating Sandra's birthday with her smiliest, silliest snaps with fellow stars over the years. Scroll through to see them all now, and just try not to smile yourself!
Sandra shared a laugh with Tom Hanks  and Bradley Cooper  at the Palm Springs Film Festival in January 2014.
Sandra and Keanu Reeves  shared the stage at the August 2006 Teen Choice Awards in LA.
Sandra was cheek to cheek with Emma Thompson  during the AFI Awards in January 2014.
Sandra and Betty White met up backstage at the August 2010 Teen Choice Awards in LA and shared a sweet hug.
Sandra and Chelsea Handler stayed close during the AFI Life Achievement Award dinner for Jane Fonda in June 2014.
She and Ryan Reynolds  attended a photocall for their romantic comedy The Proposal in June 2009.
Hugh Grant  and Sandra were full of laughs during LA's 12th Annual BAFTA/LA Britannia  Awards in November 2003.
She planted a kiss on Scarlett Johansson  during the June 2010 MTV Movie Awards in LA.
Adam Sandler  kept Sandra cracking up backstage at the MTV's September 1994 Video Music Awards held in NYC.
Sandra, Gwyneth Paltrow , and Salma Hayek  were all smiles at the 2001 VH1 Vogue Fashion Awards in NYC.
She and Bradley Cooper  put on a show for photographers at their August 2009 LA premiere of All About Steve.
She and George Clooney  made a stunning pair on the red carpet at the Venice Film Festival premiere of Gravity in August 2013.
Sandra and Keanu Reeves  were all smiles at the September 1996 ShoWest presentation in Las Vegas.
She and Ben Affleck  got goofy in front of the cameras while shooting Forces of Nature in 1999.
Sandra and Charlize Theron  snapped a photo backstage at the January 2006 SAG Awards in LA.
Sandra posed for a photo with Oprah Winfrey  at the Critics' Choice Movie Awards in January 2014.
Sandra was the belle of the ball at the Guys Choice Awards in June 2014 — she was awarded with the Decade of Hotness award by her past costars Keanu Reeves , Hugh Grant , and Matthew McConaughey .
Halle Berry  got a kiss from her during the February 2011 Oscars.
Sandra shared a hug with Anthony Mackie at a February 2011 post-Oscar bash in LA.
Sandra showed up to support her pal Ryan Reynolds  at the premiere of his film The Change-Up in August 2011.
She cracked up during a September 1996 ShoWest panel with fellow actors Mel Gibson , John Travolta , Greg Kinnear, Cameron Diaz , and James Robinson.
Meryl Streep  and Sandra posed in the press room at the 15th annual Critics' Choice Movie Awards in January 2010.
Sandra beamed on the red carpet with her friend Melissa McCarthy  as they promoted The Heat in June 2013.
She shared a laugh with her The Blind Side costar Quintin Aaron at the People's Choice Awards in January 2013.
Sandra and Kristen Stewart  shared a hilarious embrace during the May 2009 MTV Movie Awards in LA.
Ryan Gosling  gave Sandra a hug at the September 2001 LA premiere of The Believer.
Sandra and Harry Connick Jr. filmed Hope Floats together in February 1998.
Miss Congeniality 2 costars Regina King and Sandra were all smiles at the People's Choice Awards in January 2013.
George Lopez stepped out in March 2005 to support her at the LA premiere of Miss Congeniality 2.
Sandra was joined by costars Tom Hanks  and Thomas Horn at the December 2011 NYC premiere of Extremely Loud & Incredibly Close.
Sandra met up with Helen Mirren  on the red carpet at the March 2010 Oscar ceremony in LA.
She and Tim McGraw  posed for photos at their November 2009 NYC premiere of The Blind Side.
Matthew McConaughey  and Sandra shared a hug at the first annual Teen Choice Awards in August 1999.
She and Christoph Waltz shared congratulatory smiles following their Oscar wins at the March 2010 Academy Awards in LA.
She and Neil Patrick Harris  were covered in slime at the Kids' Choice Awards in March 2013.
She and Sean Hayes cracked up at the People's Choice Awards in January 2014.
Sandra mingled with Cate Blanchett  and her son Ignatius Upton during the Critics' Choice Movie Awards in January 2014.